The present work aimed to develop a novel strategy to bioremediate the petroleum hydrocarbon contaminants in the environment.Salt tolerant bacterium was isolated from Dagang oilfield,China and identified as Corynebact...The present work aimed to develop a novel strategy to bioremediate the petroleum hydrocarbon contaminants in the environment.Salt tolerant bacterium was isolated from Dagang oilfield,China and identified as Corynebacterium variabile HRJ4 based on 16 S r RNA gene sequence analysis.The bacterium had a high salt tolerant capability and biochar was developed as carrier for the bacterium.The bacteria with biochar were most effective in degradation of n-alkanes（C16,C18,C19,C26,C28） and polycyclic aromatic hydrocarbons（NAP,PYR） mixture.The result demonstrated that immobilization of C.variabile HRJ4 with biochar showed higher degradation of total petroleum hydrocarbons（THPs） up to 78.9%after 7-day of incubation as compared to the free leaving bacteria.The approach of this study will be helpful in clean-up of petroleum-contamination in the environments through bioremediation process using eco-friendly and cost effective materials like biochar.展开更多
L-Serine plays a critical role as a building block for cell growth, and thus it is difficult to achieve the direct fermentation of L-serine from glucose. In this study, Corynebacterium glutamicum ATCC 13032 was engine...L-Serine plays a critical role as a building block for cell growth, and thus it is difficult to achieve the direct fermentation of L-serine from glucose. In this study, Corynebacterium glutamicum ATCC 13032 was engineered de novo by blocking and at- tenuating the conversion of L-serine to pyruvate and glycine, releasing the feedback inhibition by L-serine to 3-phosphoglycerate dehydrogenase （PGDH）, in combination with the co-expression of 3-phosphoglycerate kinase （PGK） and feedback-resistant PGDH （PGDHr）. The resulting strain, SER-8, exhibited a lower specific growth rate and significant differ- ences in L-serine levels from Phase I to Phase V as determined for fed-batch fermentation. The intracellular L-serine pool reached （14.22_＋1.41） ~trnol gcoM-1, which was higher than glycine pool, contrary to fermentation with the wild-type strain. Furthermore, metabolic flux analysis demonstrated that the over-expression of PGK directed the flux of the pentose phosphate pathway （PPP） towards the glycolysis pathway （EMP）, and the expression of PGDHr improved the L-serine biosynthesis pathway. In addition, the flux from L-serine to glycine dropped by 24%, indicating that the deletion of the activator GlyR re- sulted in down-regulation of serine hydroxymethyltransferase （SHMT） expression. Taken together, our findings imply that L-serine pool management is fundamental for sustaining the viability of C. glutamicum, and improvement of C1 units genera- tion by introducing the glycine cleavage system （GCV） to degrade the excessive glycine is a promising target for L-serine pro- duction in C. glutamicum.展开更多
Systems metabolic engineering is a multidisciplinary area that integrates systems biology,synthetic biology and evolutionary engineering.It is an efficient approach for strain improvement and process optimization,and ...Systems metabolic engineering is a multidisciplinary area that integrates systems biology,synthetic biology and evolutionary engineering.It is an efficient approach for strain improvement and process optimization,and has been successfully applied in the microbial production of various chemicals including amino acids.In this review,systems metabolic engineering strategies including pathwayfocused approaches,systems biology-based approaches,evolutionary approaches and their applications in two major amino acid producing microorganisms:Corynebacterium glutamicum and Escherichia coli,are summarized.展开更多
We compared the potential phenotypic properties of coryneform bacteria associated with chronic prostatitis syndrome （CPS）, such as secretory inhibitor of lysozyme （SIL） and secretory inhibitor of platelet microbic...We compared the potential phenotypic properties of coryneform bacteria associated with chronic prostatitis syndrome （CPS）, such as secretory inhibitor of lysozyme （SIL） and secretory inhibitor of platelet microbicidal protein （SIPMP）. A total of 110 clinical isolates of coryneform bacteria isolated from the seminal fluid of healthy men and men with CPS were tested. SIPMP production was tested by inhibiting platelet microbicidal protein （PMP） bioactivity against Bacillus subtilis, and was expressed as percentage of inhibition of PMP bactericidal activity. SIL production was tested by inhibiting lysozyme activity against Micrococcus lysodeikticus and was expressed in microgram per millilitre of inactivated lysozyme. A significantly higher proportion of CPS strains （58.7% vs. 19.2 %） was SIPMP-positive compared with non-CPS strains （P 〈 0.01）. Of the CPS strains tested, 77.8% were SIL-positive compared with 34% of the non- CPS isolates （P 〈 0.05）. These results suggest that the diagnosis of CPS should not rely solely on classical parameters, for example, the identification and counting of microorganisms, but the functional significance of these parameters must be estimated, possibly by the concentration of different bacterial substrains, detection of opportunistic microorganisms with pathogenic properties, such as pronounced resistance to the cationic antimicrobial peptides, and/or the ability to inhibit the antimicrobial host defence factors.展开更多
Caseous lymphadenitis (CL) is a chronic infectious disease caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) that is transmitted mainly by contact with contaminated exudate wounds. Caseous lymphaden...Caseous lymphadenitis (CL) is a chronic infectious disease caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) that is transmitted mainly by contact with contaminated exudate wounds. Caseous lymphadenitis affects different species of animals and is considered an occupational zoonotic disease. CL is responsible for important economic losses in the small ruminant industry, which include decreased production, damaged quality of milk and wool, reproductive disorders, total or partial confiscation of carcasses, and depreciation of the skin. Caseous lymphadenitis disease can present in two clinical pictures: a skin or superficial picture and a visceral or deep picture. The presumptive diagnosis of CL in the skin is based on the exploration of superficial lymph nodes. These have little value in diagnosing visceral CL, where the main sign is emaciation. The prevention and control of CL involve identifying the skin condition and debriding the abscesses. In addition to the treatment of superficial lesions, the animal facilities must be repaired and adapted. To avoid exposure of negative herds to CL, new animals must be subjected to observation to identify any of the clinical manifestations. Another form of control is vaccination, though only some countries have commercial vaccines. General information on the etiological agent and its characteristics can be used to improve the understanding of this disease.展开更多
基金the National Natural Science Foundation of China (No.31270544,41473070)the Hi-Tech Research and Development Program (863) of China (No.2013AA06A205)the 863 achievement transformation program in Tianjin (No.14RCHZSF00144)
文摘The present work aimed to develop a novel strategy to bioremediate the petroleum hydrocarbon contaminants in the environment.Salt tolerant bacterium was isolated from Dagang oilfield,China and identified as Corynebacterium variabile HRJ4 based on 16 S r RNA gene sequence analysis.The bacterium had a high salt tolerant capability and biochar was developed as carrier for the bacterium.The bacteria with biochar were most effective in degradation of n-alkanes（C16,C18,C19,C26,C28） and polycyclic aromatic hydrocarbons（NAP,PYR） mixture.The result demonstrated that immobilization of C.variabile HRJ4 with biochar showed higher degradation of total petroleum hydrocarbons（THPs） up to 78.9%after 7-day of incubation as compared to the free leaving bacteria.The approach of this study will be helpful in clean-up of petroleum-contamination in the environments through bioremediation process using eco-friendly and cost effective materials like biochar.
基金supported by grants from Ministry of Science and Technology of China (Grant Nos.2008ZX09401-05 and 2010ZX09401-403)the National Natural Science Foundation of China (Grant No. 31100074)Chinese Academy of Sciences (Grant No. XBXA-2011-009)
文摘L-Serine plays a critical role as a building block for cell growth, and thus it is difficult to achieve the direct fermentation of L-serine from glucose. In this study, Corynebacterium glutamicum ATCC 13032 was engineered de novo by blocking and at- tenuating the conversion of L-serine to pyruvate and glycine, releasing the feedback inhibition by L-serine to 3-phosphoglycerate dehydrogenase （PGDH）, in combination with the co-expression of 3-phosphoglycerate kinase （PGK） and feedback-resistant PGDH （PGDHr）. The resulting strain, SER-8, exhibited a lower specific growth rate and significant differ- ences in L-serine levels from Phase I to Phase V as determined for fed-batch fermentation. The intracellular L-serine pool reached （14.22_＋1.41） ~trnol gcoM-1, which was higher than glycine pool, contrary to fermentation with the wild-type strain. Furthermore, metabolic flux analysis demonstrated that the over-expression of PGK directed the flux of the pentose phosphate pathway （PPP） towards the glycolysis pathway （EMP）, and the expression of PGDHr improved the L-serine biosynthesis pathway. In addition, the flux from L-serine to glycine dropped by 24%, indicating that the deletion of the activator GlyR re- sulted in down-regulation of serine hydroxymethyltransferase （SHMT） expression. Taken together, our findings imply that L-serine pool management is fundamental for sustaining the viability of C. glutamicum, and improvement of C1 units genera- tion by introducing the glycine cleavage system （GCV） to degrade the excessive glycine is a promising target for L-serine pro- duction in C. glutamicum.
基金This research was supported by National High Technology Research and Development Program of China(2015AA021003)National Natural Science Foundation of China(31470211)+1 种基金Natural Science Foundation of Tianjin(17JCQNJC09500)Foundation(No.2016IM104)of Key Laboratory of Industrial Fermentation Microbiology of Ministry of Education and Tianjin Key Lab of Industrial Microbiology(Tianjin Universityof Science&Technology).
文摘Systems metabolic engineering is a multidisciplinary area that integrates systems biology,synthetic biology and evolutionary engineering.It is an efficient approach for strain improvement and process optimization,and has been successfully applied in the microbial production of various chemicals including amino acids.In this review,systems metabolic engineering strategies including pathwayfocused approaches,systems biology-based approaches,evolutionary approaches and their applications in two major amino acid producing microorganisms:Corynebacterium glutamicum and Escherichia coli,are summarized.
文摘We compared the potential phenotypic properties of coryneform bacteria associated with chronic prostatitis syndrome （CPS）, such as secretory inhibitor of lysozyme （SIL） and secretory inhibitor of platelet microbicidal protein （SIPMP）. A total of 110 clinical isolates of coryneform bacteria isolated from the seminal fluid of healthy men and men with CPS were tested. SIPMP production was tested by inhibiting platelet microbicidal protein （PMP） bioactivity against Bacillus subtilis, and was expressed as percentage of inhibition of PMP bactericidal activity. SIL production was tested by inhibiting lysozyme activity against Micrococcus lysodeikticus and was expressed in microgram per millilitre of inactivated lysozyme. A significantly higher proportion of CPS strains （58.7% vs. 19.2 %） was SIPMP-positive compared with non-CPS strains （P 〈 0.01）. Of the CPS strains tested, 77.8% were SIL-positive compared with 34% of the non- CPS isolates （P 〈 0.05）. These results suggest that the diagnosis of CPS should not rely solely on classical parameters, for example, the identification and counting of microorganisms, but the functional significance of these parameters must be estimated, possibly by the concentration of different bacterial substrains, detection of opportunistic microorganisms with pathogenic properties, such as pronounced resistance to the cationic antimicrobial peptides, and/or the ability to inhibit the antimicrobial host defence factors.
文摘Caseous lymphadenitis (CL) is a chronic infectious disease caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) that is transmitted mainly by contact with contaminated exudate wounds. Caseous lymphadenitis affects different species of animals and is considered an occupational zoonotic disease. CL is responsible for important economic losses in the small ruminant industry, which include decreased production, damaged quality of milk and wool, reproductive disorders, total or partial confiscation of carcasses, and depreciation of the skin. Caseous lymphadenitis disease can present in two clinical pictures: a skin or superficial picture and a visceral or deep picture. The presumptive diagnosis of CL in the skin is based on the exploration of superficial lymph nodes. These have little value in diagnosing visceral CL, where the main sign is emaciation. The prevention and control of CL involve identifying the skin condition and debriding the abscesses. In addition to the treatment of superficial lesions, the animal facilities must be repaired and adapted. To avoid exposure of negative herds to CL, new animals must be subjected to observation to identify any of the clinical manifestations. Another form of control is vaccination, though only some countries have commercial vaccines. General information on the etiological agent and its characteristics can be used to improve the understanding of this disease.
